Ambient Stress in Subduction Forearcs Constrained by Numerical Models and Earthquake Static Stress Drop Values

Stress in active subduction forearcs is controlled primarily by friction along the megathrust and the gravitational force. The competing deviatoric compressive and tensional stresses generated by megathrust friction and gravity, respectively, are of the same order of magnitude and result in very low deviatoric stress in the forearc. The near neutral stress state in subduction forearcs is supported by observations of stress reversal, that is a change from deviatoric compression to deviatoric tension, caused by very small megathrust shear stress drops (